Changes In SHRSP Research Articles

OP.5D.02] TRANSCRIPTOMIC CHANGES IN EARLY PREGNANCY-ASSOCIATED UTERINE ARTERY REMODELLING IN STROKE PRONE SPONTANEOUSLY HYPERTENSIVE RAT

Objective: Deficient spiral artery remodelling is an early gestational defect linked to a number of pregnancy complications such as pre-eclampsia and gestational hypertension. We have previously demonstrated abnormal uterine artery remodelling at gestational day 18 in the stroke prone spontaneously hypertensive (SHRSP) rat. In this study, we examined the early uterine artery structural and functional changes in SHRSP and normotensive Wistar Kyoto (WKY) rats alongside changes in the transcriptome profile. Design and method: Female SHRSP and female WKY rats were time mated at 12 weeks of age ± 4 days. At gestational day 6 (GD6) uterine arteries were dissected and pressure and wire myography performed to assess vascular structure and functional properties. RNAseq (Illumina platform; ribosome depleted, 50 million reads) was performed in uterine arteries from SHRSP and WKY at GD6 and from non-pregnant rats. RNAseq data (FDR < 0.05, FPKM > 1.0) was interpreted using Ingenuity® Pathway Analysis. Results: No significant structural or functional differences were observed in uterine arteries from SHRSP and WKY rats at GD6; cross-sectional area (57.7 ± 1.2 × 103 μm2 vs 67.5 ± 4.2 × 103 μm2), maximal constriction to noradrenaline (41.7 ± 8.1 kPa vs 49.5 ± 9.4 kPa), vasorelaxation to carbachol (76.1 ± 3.9% vs 82.2 ± 3.2%) and SNP (60.5 ± 6.2% vs 58.9 ± 5.8%) (% of maximum constriction) for WKY and SHRSP respectively. RNAseq conducted at GD6, prior to vascular remodelling or functional changes, identified 551 differentially expressed genes between pregnant WKY and pregnant SHRSP; including genes involved in uterine artery vasculogenesis (p-value = 3.78 × 10−10), e.g. angiotensinogen (3.2 fold change, (fc)); angiogenesis (p-value = 3.10 × 10−11), e.g. thrombospondin 4 (4.9 fc); endothelial cell proliferation (p-value = 3.94 × 10−8), e.g. vascular endothelial growth factor D (2.1 fc); and the endothelial nitric oxide synthase pathway (p-value = 3.16 × 10−4), e.g. ryanodine receptor 2 (2.0 fc). Pregnancy resulted in SHRSP-specific increase in expression of NADPH oxidase regulatory subunits p47phox (2.1 fc), p67phox (2.0 fc), p40phox (2.9 fc) p22phox (1.8 fc) and gp91phox (1.8 fc). Conclusions: Uterine artery gene expression during early pregnancy is markedly different between SHRSP and WKY prior to any observed functional and structural changes. Transcriptome profiling implicates pathogenic changes in vasculogenesis and angiogenesis pathways, and endothelial dysfunction, as well as evidence of abnormal oxidative stress response in SHRSP uterine arteries.

Chronic administration of the soluble epoxide hydrolase (sEH) inhibitor, AUDA, ameliorates end‐organ damage in stroke‐prone hypertensive rats (SHRSP)

We have shown that treatment with the sEH inhibitor, AUDA (12‐(3‐adamantan‐1‐yl‐ureido) dodecanoic acid) for 10 days can markedly ameliorate the early salt‐sensitive pathologic changes in SHRSP (Li et al., Frontiers in Bioscience, 2008). In the present study, we examined whether long‐term treatment with AUDA (6 weeks) would protect against the development of severe end‐organ damage in these rats. Fifteen male SHRSP were maintained on stroke‐prone rodent diet and 1% NaCl drinking solution starting at 7 weeks of age. Eight SHRSP received AUDA (10 mg/Kg) once daily by gavage and 5 littermates served as controls. After 6 weeks of treatment, all of the control SHRSP developed proteinuria and exhibited histological evidence of severe widespread nephrosclerosis. In contrast, 5 AUDA‐treated SHRSP showed no proteinuria or renal damage and 3 AUDA‐treated SHRSP showed proteinuria but reduced renal damage relative to controls. Overall, proteinuria was reduced (142±25 vs 54±23 mg/d, P&lt;0.05) and renal cortical cytochrome P450 2C11 protein expression was increased (P&lt;0.05) and there was a highly significant inverse correlation between these parameters (P&lt;0.0005). Pre‐terminal systolic blood pressure did not differ between the groups. These data suggest that the sEH inhibition as an intervention to maintain or increase EET levels may serveas a therapeutic approach to ameliorate salt‐sensitive end‐organ damage in SHRSP.

Soluble epoxide hydrolase inhibitor, AUDA, prevents early salt-sensitive hypertension

In stroke-prone spontaneously hypertensive rats (SHRSP) end-organ damage is markedly accelerated by high-salt (HS) intake. Since epoxyeicosatrienoic acids (EETs) possess vasodepressor and natriuretic activities, we examined whether a soluble epoxide hydrolase (sEH) inhibitor, 12-(3-adamantan-1-yl-ureido)-dodecanoic acid (AUDA), to inhibit the metabolism of EETs, would protect against pathologic changes in SHRSP. Seven-week-old male SHRSP were treated as follows: normal salt (NS), NS + AUDA, HS and HS + AUDA. Systolic blood pressure (SBP) (205 +/- 4 v 187 +/- 7 mmHg) and proteinuria (3.7 +/- 0.2 v 2.6 +/- 0.2 mg/6 h), but not plasma EETs (11.0 +/- 0.9 v 9.7 +/- 1.1 ng/ml), were significantly increased at 9 weeks of age in HS v NS SHRSP. HS was associated with fibrinoid degeneration and hypertrophy of arterioles in the kidney and perivascular fibrosis and contraction band necrosis in the heart. AUDA ameliorated these early salt-dependent changes in saline-drinking SHRSP and increased plasma levels of EETs but did not affect water and electrolyte excretion. sEH inhibition may provide a therapeutic strategy for treating salt-sensitive hypertension and its sequelae.

In Vivo Activation of Rat Aortic Platelet-Derived Growth Factor and Epidermal Growth Factor Receptors by Angiotensin II and Hypertension

It is unclear whether the previous in vitro evidence of a link between angiotensin II (Ang II) and growth factor receptors can apply to the in vivo situation. In this study, we examined vascular platelet-derived growth factor (PDGF) and epidermal growth factor (EGF) receptor activation in stroke-prone spontaneously hypertensive rats (SHRSP) and the role of Ang II. Tyrosyl phosphorylation of the growth factor receptors was determined by Western blot analysis coupled with immunoprecipitation. Tyrosyl phosphorylation of the aortic PDGF beta-receptor, but not the EGF receptor, was chronically increased in SHRSP with hypertension, compared with normotensive rats, being accompanied by increased extracellular signal-regulated kinase (ERK) activity. Treatment of SHRSP with ACE inhibitors (perindopril or enalapril) significantly reduced aortic PDGF beta-receptor tyrosyl phosphorylation and ERK activity, whereas treatment with hydralazine failed to reduce these activities. Therefore, these aortic changes in SHRSP were mediated by Ang II in response to vascular ACE. Ang II was infused into rats to examine the effects on aortic growth factor receptors. Chronic Ang II infusion, via the angiotensin type 1 receptor, significantly increased activation of the aortic PDGF beta-receptor but not the EGF receptor. Thus, the aortic PDGF beta-receptor, activated by ACE-mediated Ang II, seems to be responsible for vascular remodeling in hypertensive rats.

Effect of Chronic Treatment with Perindopril on Endothelium-dependent Relaxation of Aorta and Carotid Artery in SHRSP.

Endothelium-dependent relaxation of aorta and carotid artery from stroke-prone spontaneously hypertensive rats (SHRSP) and the effect of chronic treatment of SHRSP with perindopril, an angiotensin converting enzyme inhibitor, on endothelium-dependent relaxation were studied. Endothelium-dependent relaxation was induced by acetylcholine (ACh) in preparations of SHRSP and normotensive Wistar Kyoto rats (WKY) precontracted with noradrenaline. The ACh-induced relaxation in both preparations was abolished by L-nitroarginine. The ACh-induced relaxation was impaired in preparations from SHRSP and contraction was observed at high concentrations of ACh. In the presence of indomethacin, impairment of endothelium-dependent relaxation in SHRSP was minimized and the contraction was inhibited. The relaxation with sodium nitroprusside did not differ between the preparations from WKY and SHRSP. Treatment of SHRSP with perindopril (2 mg/kg/day) for 6 weeks decreased systolic blood pressure and improved the ACh-induced relaxation of aorta and carotid artery. The treatment inhibited the contraction by higher concentrations of ACh in the presence of L-nitroarginine. These results indicate that the impairment of endothelium-dependent relaxation in aorta and carotid artery of SHRSP may be caused by the reduced availability of nitric oxide. The perindopril-treatment may prevent these changes in SHRSP.

Antihypertensive effect of docosahexaenoic acid in stroke-prone spontaneously hypertensive rats

Docosahexaenoic acid (DHA) is an n-3 unsaturated fatty acid derived from fish oils. The precise mechanisms of DHA actions are still obscure. Especially, the antihypertensive effect of DHA has not yet been elucidated. Stroke-prone spontaneously hypertensive rats (SHRSP) provide the best available model for essential hypertension and stroke. The present study was undertaken to elucidate the effects of long term administration of DHA on blood pressure and stroke-related behavior in SHRSP. The blood pressure of DHA-treated SHRSP was lowered significantly as compared with that of non-treated SHRSP. DHA produced an ameliorative effect on the decreased passive avoidance response in SHRSP. DHA also improved the behavioral changes in spontaneous motor activity of SHRSP. DHA-treated SHRSP produced a significant decrease in the levels of total cholesterol, low density lipoprotein, triglycerides, lipid peroxide, serum creatinine and blood urea nitrogen as compared with those in non-treated SHRSP. These findings indicate that the DHA-induced antihypertensive action may be associated with the amelioration of both serum lipid alteration and renal dysfunction in non-treated SHRSP. Moreover, DHA-treated SHRSP maintain the normal levels of acetylcholine and choline concentrations in the hippocampus and cerebral cortex. These findings demonstrated that DHA produced an ameliorative effect on cholinergic nerve dysfunction in SHRSP. The improved cholinergic nerve function induced by DHA might have an inhibitory effect on stroke-related behavior in SHRSP. The present study suggests that long term administration of DHA may suppress the development of hypertension and stroke-related behavioral changes in SHRSP.

Fundus and Histopathological Changes in SHRSP after Administration of Three Kinds of Antihypertensive Agents and Ascorbic acid

Fundus and Histopathological Changes in SHRSP after Administration of Three Kinds of Antihypertensive Agents and Ascorbic acid

Myocyte hypertrophy and capillarization in spontaneously hypertensive stroke-prone rats.

Stroke-prone spontaneously hypertensive rats (SHRSP) are liable to suffer a stroke between 25 and 40 weeks of age. Left ventricular capillarity was studied in 40-week-old SHRSP to clarify the effects of hypertrophic changes in cardiomyocytes on oxygen transport capacity within the tissue. The innermost region of the left ventricular subendocardium at the level of the maximum diameter of the heart was investigated. Methods for sectioning and differential staining of arteriolar, intermediate and venular capillaries, and measurements for determining capillarity parameters were as previously described. Total capillary density decreased, while capillary domain areas increased along the whole capillary pathway. These changes in SHRSP seemed unfavorable for oxygen supply to ventricular tissues. To minimize the effects of the adverse changes, the ratio of the capillary to myocyte number increased markedly. The proportion of arteriolar capillaries increased and the venular proportion decreased.

Fundus and Histopathological Changes in SHRSP after Administration of Antihypertensive Agents-A Comparison of Nifedipine and Captopril

Fundus and Histopathological Changes in SHRSP after Administration of Antihypertensive Agents-A Comparison of Nifedipine and Captopril

Pharmacological studies on a new dihydrothienopyridine calcium antagonist, S‐312‐d: Therapeutic effects of s‐312‐d on cerebral metabolic impairment in stroke‐prone spontaneously hypertensive rats

AbstractThe therapeutic effects of S‐312‐d on cerebral metabolic impairment were investigated in the stroke‐prone spontaneously hypertensive rats (SHRSP) with apparent stroke symptoms. S‐312‐d was orally administered 10 mg/kg/day (25 μmol/kg/day) to the SHRSP group (SP‐312) for 3 weeks. Several stroke symptoms such as piloerection, hyperreactivity, and limb paralysis in SHRSP were markedly alleviated in SP‐312. Their body weight and food intake also increased. The hypotensive and positive chronotropic effects with S‐312‐d were recovered to pre‐drug levels at 24 h after daily administration. The increases of water, Na+ and Ca2+ and the decreases of K+ and Mg2+ in the cortex of SHRSP administered 1% gum arabic solution (SP‐cont) were significantly improved in SP‐312. The increases of glucose and lactate/pyruvate ratio in the cortex of SP‐cont were also significantly reduced in SP‐312, while the recoveries of the decreased ATP and creatine phosphate in the cortex of SP‐312 were slight. The cholinergic and monoaminergic neurotransmitters in the brain were generally decreased in SP‐cont. The decreased acetylcholine (ACh) and choline acetyltransferase activity (CAT) in the cortex of SP‐cont were significantly restored in SP‐312. In the cortex, the decreased dopamine (DA) in SP‐cont was significantly restored, while the decreased norepinephrine (NE) and 5‐hydroxytryptamine (5‐HT) in SP‐cont were only slightly recovered in SP‐312. However, the decreased NE and 5‐HT in SP‐cont showed marked recovery in the hippocampus of SP‐312. Many biochemical deteriorations in cerebral organs such as marked edema, increases of Na+ and Ca+ contents, and decreases of several neurotransmitters in symptomatic SHRSP, which had some characteristic symptoms of stroke, seemed to be improved by the several pharmacological effects resulting from Ca2+ antagonistic effects of S‐312‐d. These data suggests that S‐312‐d can prevent the deteriorating metabolic changes in SHRSP following the cerebral stroke. © 1994 Wiley‐Liss, Inc.

Effects of YM-14673, a new thyroid-releasing hormone analogue, on neurological in stroke-prone spontaneously hypertensive rats

The effects of YM-14673, a new thyroid-releasing hormone (TRH) analogue (N α-[[(S)-4-oxo-2-azetidinyl]carbonyl]-L-histidyl-L-prolinamide dihydrate), on neurological deficits were examined in stroke-prone spontaneously hypertensive rats (SHRSP). The neurological deficits were evaluated for more than 21 days after stroke. Administration of YM-14673 was started the day stroke was observed and repeated daily for 3 weeks. YM-14673 (0.1 and 0.3 mg/kg i.p.) improved the neurological deficits and reduced mortality. These results demonstrate that YM-14673 mitigates cerebral ischemic changes in SHRSP.

Electrocardiogramical and Morphological Examinations of Myocardial Changes in SHRSP after Injection of Isoproterenol

Electrocardiogramical and Morphological Examinations of Myocardial Changes in SHRSP after Injection of Isoproterenol

Relationship between Arterial Runways and the Development of Hypertensive Vascular Changes in Certain SHRSP Organs

1) Specific arterial runways such as right angular and recurrent branchings, sharp returnings, loopings, convolutions and long runways are a local factor in the incidence of hypertensive vascular changes in SHRSP. 2) The serial recurrence of the above factors in various combination in the arterial runways accelerates the incidence of vascular changes; e.g., in the kidneys, the testes and the adrenals. 3) In arterial runways which form arcades, vascular changes were found in the convexity of those terminal arcades which were composed of ar-teries of over 40μ in radius; e.g., in the mesentery and the uterus. 4) The lack of specific branchings in the shorter runways of the ovarian arteries results in a lower vascular change incidence rate in those organs.

Platelet survival studies in stroke-prone spontaneously hypertensive rats (SHRSP).

Platelet survival was studied by using 51Cr-labeled platelets in stroke-prone spontaneously hypertensive rats (SHRSP), stroke-resistant SHR (SHRSR) and normotensive control rats of the Wistar-Kyoto (WK) strain. Relatively young animals of the same age prior to the development of cerebrovascular lesions (cerebral infarction and/or hemorrhage) were used. Platelet half-life time in SHRSP was slightly but significantly shorter than in any other groups or rats, irrespective of the type of platelet donors. Mean platelet consumption was also significantly increased in SHRSP only. Platelets of SHRSP injected into SHRSR showed normal survival. These data support the concept that the shortened platelet survival in SHRSP is brought about by some extracorpuscular abnormalities. Although the vascular changes in SHRSP could be the most likely explanation for the shortened platelet survival, its mechanism remains to be solved. This investigation suggests that studies of the platelet survival in hypertension may be useful in predicting the development of stroke before its clinical recognition.